Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Java Development Process Developing Java Programs with • Step 1: Editing the Program • Step 2: Compiling the Program JCreator: • Step 3: Running the Program Editing, Compiling and Running 1 2 JCreator Java Development • Several programs that perform different tasks used to edit, compile and run – Java Development Kit (JDK) – available free from http://java.sun.com/ • Integrated Development Environments (IDE) – – – – Borland’s JBuilder Metrowerk’s CodeWarrior Nottingham’s CourseMarker JCreator • Editor with ability of colour coding. • Automated Indention • Code Folding • Debugger Interface. • More and more facilities. 4 Example: Colour Coding Correct Code 5 • Easy to use. • Word Completion 3 Incorrect Code • Powerful IDE (Integrated Development Environment) for Java. How to run JCreator? • Click on ‘Start’ Menu • Choose ‘Program’ • Find ‘JCreator’ • Click on ‘JCreator’ OR • double click on ‘JCreator’ shortcut 6 1 How to create a file? Step 1: Editing the Program • Creating a file • Saving your file (java program) • Java file names 7 • Start writing your program. • Save your program by pressing Ctrl+S OR selecting ‘Save’ from ‘File’ Menu. • • • • • Choose ‘New’ from ‘File’ Menu OR press Ctrl+N. Click on ‘Files’ tab on ‘New’ box. Select ‘Java File’. Enter your file name (e.g. test). Select the location that you want to place your program (e.g. h:\MyProgram). • Select ok. 8 Some important issues: • Java file names are case sensitive. • Java programs should have .java extensions. you don’t have to worry about that as JCreator does that automatically for you. 9 10 Step 2 : Compile the program When you compile… • Select ‘Compile File’ from ‘Build’ Menu. OR use the shortcut. 11 • The Java Compiler translates your program into Java bytecode, which is interpreted by the Java Virtual Machine (JVM). • Successful compilation will create a bytecode .class file 12 2 After the compilation process… • You may have no errors: – Your program is ready to be executed. So go to step 3. • You may have some errors: – Go back to your program and try correct it using the information that the JCreator compiler gives you. – Then compile again. – If there are no errors, go to step 3 for running your program. Example: Compilation Error class test { public static void main(String argv []) { // prints "Hello World" system.out.println("Hello World"); } } 9. system.out.println("Hello World"); ^----^ *** Semantic Error: No field named "system" was found in type "test". 13 14 Example: Compilation Error class test { public static void main(String argv []) { // prints "Hello World" System.out.println("Hello World") } } 9. System.out.println("Hello World") Example: Compilation Error class test { public static void main(String argv [] { // prints "Hello World" System.out.println("Hello World"); } } 6. public static void main(String argv [] ^-------------------------------^ *** Syntax: ";" inserted to complete BlockStatementsopt ^ *** Syntax: ) expected after this token 15 Example: Compilation Error class test { public static void main(String argv []) { / prints "Hello World" System.out.println("Hello World"); } } 8. 16 Example: Compilation Error class test { public static void main(String argv []) { // prints "Hello World" System.out.println("Hello World"); } 5. { . . . / prints "Hello World" 10. ^--------------------^ *** Syntax: Unexpected symbols ignored } --------> *** Syntax: "}" inserted to complete ClassBody 17 18 3 Step 3: Run your Program Example: Run Time Error At this stage, the JVM interprets your program, which has been loaded into memory. To to run your program: • Select ‘Execute File’ from ‘Build’ Menu OR • Click on shortcut from toolbar. 19 20 If you want to … • Save your program with different name: Select ‘Save As’ from ‘File’ menu and enter your desired file name and the location you need to put it. • Open an existing file: Select ‘open’ from ‘File’ menu (or press Ctrl + O) and find your file from the right directory. • Copy selected lines of code somewhere else: Highlight the code with the help of mouse or Shift + Arrow key. Press Ctrl + C or choose ‘copy’ from ‘Edit’ Menu. Go to the destination line. Press Ctrl + V or select ‘paste’ from ‘Edit’ Menu. • Move selected lines of code somewhere else: Highlight the code with the help of mouse or Shift + Arrow key. • Print your file: Select ‘print’ from ‘File’ menu (or press Ctrl + P). Press Ctrl + X or choose ‘cut’ from ‘Edit’ Menu. Go to the destination line. Press Ctrl + V or select ‘paste’ from ‘Edit’ Menu. 21 22 • Undo Press Ctrl + Z or select ‘undo’ from ‘Edit’ menu. • Find a word(s) in file: Press Ctrl + F or select ‘find’ from ‘Search’ menu. Enter the word(s) you want to find. adjust the options in Find box to your desire. click on ‘find next’. Common Syntax Errors • Leaving out symbols such as: • ; • } • ) • Ignore symbol ‘+’ between two literal strings in print statement For more shortcut look at ‘advanced’ from ‘Edit’ Menu. For more information on JCreator look at http://www.jcreator.com/ 23 • System.out.println("Hello" "World"); 24 4 Common Semantic Errors • Failing to define a variable before it is used. • Use of non-static variables inside a static method. • Type mismatch. • Using a variable that has not been initialised • Declaring an identifier more than once. 25 5